Many desktop computers and network systems run anti-virus programs to prevent users from inadvertently invoking malicious code, such as a virus, worm, Trojan horse, adware, spyware, etc. Many of these anti-virus programs are loaded into the runtime environment after the operating system is loaded. Such anti-virus programs cannot detect and stop the execution of virus data in the boot sector of the primary hard disk drive that is executed before the operating system and anti-virus program are installed. For such boot sector viruses, by the time the anti-virus program is loaded and running, the virus may have spread throughout the system and to any attached storage devices or over any attached network devices.
To remove malicious code from the boot sector, the user may boot the system from a floppy disk or other boot device and run an anti-viral program from the boot disk to scan and remove any viruses from the boot sector. Further, some products provide a facility to encrypt and prevent modification to the system areas, such as the boot sector, of the hard disk drive to allow detection of changes to the boot sector and system areas of the hard disk.